GC: n
CT: This report summarizes analytical evaluation of crack-opening areas and leak rates of superheated steam through flaws in steam generator tubes and erosion of neighboring tubes due to jet impingement of superheated steam with entrained particles from core debris created during severe accidents. An analytical model for calculating crack-opening area as a function of time and temperature was validated with tests on tubes with machined flaws. A three dimensional computational fluid dynamics code was used to calculate the jet velocity impinging on neighboring tubes as a function of tube spacing and crack-opening area. Erosion tests were conducted in a high-temperature, high-velocity erosion rig at the University of Cincinnati, using micrometer-sized nickel particles mixed in with high-temperature gas from a burner. The erosion results, together with analytical models, were used to estimate the erosive effects of superheated steam with entrained aerosols from the core during severe accidents.
S: USNRC – http://www.nrc.gov/reading-rm/doc-collections/nuregs/contract/cr6756 (last access: 9 December 2014)
N: 1. Superheat (v): 1827 (implied in superheated) “to heat to a very high degree,” specifically of steam until it resembles a perfect gas, from super- + heat (v.). Related: Superheating. Steam (n): Old English steam “vapor, fume, water in a gaseous state,” from Proto-Germanic *staumaz (cognates: Dutch stoom “steam”), of unknown origin. Meaning “vapor of boiling water used to drive an engine” is from 1690s, hence steam age (1828) and many figurative uses, such as let off steam (1831, literal), blow off steam (1857, figurative), full-steam (1878), get up steam (1887, figurative). Steam heat is from 1820s in thermodynamics; as a method of temperature control from 1904.
2. Superheated steam is created by further heating wet or saturated steam beyond the saturated steam point. This yields steam that has a higher temperature and lower density than saturated steam at the same pressure. Superheated steam is mainly used in propulsion/drive applications such as turbines, and is not typically used for heat transfer applications.
S: 1. OED – http://www.etymonline.com/index.php?allowed_in_frame=0&search=superheated&searchmode=none (last access: 9 December 2014); http://www.etymonline.com/index.php?allowed_in_frame=0&search=steam&searchmode=none (last access: 9 December 2014). 2. TLV – http://www.tlv.com/global/TI/steam-theory/types-of-steam.html (last access: 9 December 2014).
GV: super-heated steam
S: GDT
SYN: superheated vapor, superheated vapour.
S: TERMIUMPLUS
CR: [solar steam plant], solar thermal collector, solar thermal energy.
